Computer drawing programs assist a computer user in producing and editing such drawings as block diagrams, flowcharts, maps, office layouts, organizational charts, project schedules, and other types of drawings.
Within each drawing can be a multitude of shapes and symbols. For instance, simple geometric shapes or objects, such as squares, rectangles, triangles and circles can indicate people, places and things. It is often desirable and aesthetically pleasing for shapes to be aligned in some manner. For instance, in an office layout diagram including several squares indicating workers' cubicles, it is desirable to have all of the squares line up in a straight line so that one edge will look like an aisle or hallway. This alignment proves difficult when objects are manually dragged and placed in a diagram.
To assist users align objects in drawings, some drawing programs support a static gridline feature. Static gridlines, generally, act as electronic graph paper, providing straight lines to assist the user align several individual shapes. An additional feature, called “snap”, automatically aligns the shapes that the computer determines are proximately located to one of the static gridlines. When proximity to a static gridline is sensed during placement of a shape, the computer automatically aligns the shape to the proximal static gridline. The snap feature allows the users to quickly and accurately align the individual shapes, and produce an aesthetically pleasing drawing.
One difficulty brought on by snap gridlines is that the user must conform the placement of the shapes to the gridlines already on the screen. When the user wants to place shapes at areas other than where the grids are placed, the user is again forced to place these shapes by freehand.
In view of the need by many users for assistance in placing objects in a drawing program, a system that dynamically changes the gridlines according to objects already placed on the drawing screen and additionally providing snapping to the dynamically placed gridlines would have significant utility.